Common Coronaviruses Are Highly Seasonal

Most cases peak during winter months, with highest infection frequency in children younger than age 5 years

WEDNESDAY, April 15, 2020 (HealthDay News) — Common coronaviruses circulate seasonally, according to a study published online April 4 in the Journal of Infectious Diseases.

Arnold S. Monto, M.D., from the University of Michigan in Ann Arbor, and colleagues used data from the Household Influenza Vaccine Evaluation study, in which 890 to 1,441 individuals were followed on a weekly basis for 10 years, to track the occurrence of acute respiratory infections. During illness, specimens were collected and tested for human coronavirus (HCoV) types OC43, 229E, HKU1, and NL63.

The researchers identified 993 HCoV infections over eight years, with OC43 most commonly seen and 229E the least commonly seen. Between December and April/May was when HCoVs were detected, with a peak in January/February. The highest infection frequency was seen in children <5 years (18 per 100 person-years), with little variation in frequency among older age groups (range: 7 to 11 per 100 person-years). Medical consultation was needed overall in 9 percent of adult cases and 20 percent of cases in children. Just over one-quarter of cases were acquired from an infected household contact. Between index and household-acquired cases, the serial interval ranged from 3.2 to 3.6 days and the secondary infection risk ranged from 7.2 to 12.6 percent by type.

“Even though the seasonal coronaviruses found in Michigan are related to severe acute respiratory syndrome coronavirus 2, we do not know whether that virus will behave like the seasonal coronaviruses,” Monto said in a statement.